Abstract
OBJECTIVES: The finding that migrants to high-income countries have lower rates of morbidity and mortality than non-migrants, controlling for socio-economic position, is often attributed to the “healthy migrant” hypothesis, which suggests that only the healthiest individuals choose to migrate. This prospective study investigates the healthy migrant hypothesis in a cohort of British emigrants using pre-migration health indicators. We also investigate how early-life health characteristics relate to age at emigration and whether or not the emigrant returned home.
METHODS: Data are from the Medical Research Council National Survey of Health and Development, a nationally representative cohort study of people born in England, Scotland or Wales in March 1946. Childhood socio-economic position, health and cognitive ability were compared between 4,378 non-emigrants and 984 emigrants. Of the emigrants, 427 emigrated before age 20 and 557 after that age; 602 emigrants remained abroad and 382 returned home.
RESULTS: Emigrants had better childhood health (especially greater height), higher childhood socio-economic position and better childhood cognitive ability at age 8 than non-emigrants. Return emigrants were very similar to emigrants who remained abroad.
CONCLUSIONS: We found support for the healthy migrant hypothesis in a cohort of British emigrants. Our findings improve an understanding of how health is distributed within and across nations.
Keywords: The MRC National Survey of Health and Development, healthy migrants, healthy immigrants, life course, birth cohort
Résumé
OBJECTIFS : La constatation selon laquelle les migrants vers les pays à revenu élevé ont des taux de morbidité et de mortalité inférieurs à ceux des non-migrants, en tenant compte des effets du statut socioéconomique, est souvent imputée à l’hypothèse du « migrant en bonne santé », qui suggère que seules les personnes dont la santé est la meilleure choisissent d’émigrer. Notre étude prospective teste l’hypothèse du migrant en bonne santé dans une cohorte d’émigrants britanniques à l’aide d’indicateurs sanitaires avant la migration. Nous enquêtons aussi sur les liens entre les caractéristiques de santé en bas âge et l’âge au moment de l’émigration, et sur le retour ou non de l’émigrant dans son pays natal.
MÉTHODE : Nos données proviennent de la National Survey of Health and Development du Medical Research Council, une étude de cohorte représentative à l’échelle nationale des personnes nées en Angleterre, en Écosse ou au pays de Galles en mars 1946. Nous avons comparé le statut socioéconomique, la santé et les capacités cognitives durant l’enfance de 4378 non-émigrants et de 984 émigrants. Parmi les émigrants, 427 ont émigré avant l’âge de 20 ans et 557 après cet âge; 602 émigrants sont restés à l’étranger et 382 sont retournés dans leur pays natal.
RÉSULTATS : Les émigrants avaient eu une meilleure santé durant l’enfance (en particulier, ils étaient de taille plus grande), un statut socioéconomique plus élevé durant l’enfance et de meilleures capacités cognitives durant l’enfance, à l’âge de 8 ans, que les non-émigrants. Les émigrants de retour étaient très semblables aux émigrants restés à l’étranger.
CONCLUSIONS : Nous avons trouvé des preuves à l’appui de l’hypothèse du migrant en bonne santé dans une cohorte d’émigrants britanniques. Nos constatations permettent de mieux comprendre comment la santé est répartie à l’intérieur des pays et d’un pays à l’autre.
Mots Clés: National Survey of Health and Development (enquête du MRC), migrants en bonne santé, immigrants en bonne santé, parcours de vie, cohorte de naissance
Footnotes
Funding: E. Fuller-Thomson is supported by the Sandra Rotman Chair in Social Work. R. Cooper and D. Kuh are supported by the UK Medical Research Council (Programme code: MC_UU_12019/1). The MRC National Survey of Health and Development is funded by the UK Medical Research Council.
Conflict of Interest: None to declare.
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